<?php
class Layout{
    public static function nav($template,$group_id){
        $group_id = intval($group_id);
        $model = new NavModel;
        $data['data'] = $model->where(['group_id' => $group_id])->select();
        $xml = Yaf_Registry::get('tpl')->render($template,$data);
        echo $xml;
    }
}